package com.fcat.base.common.util;

import com.fcat.base.common.po.TreeNode;

import java.util.ArrayList;
import java.util.List;


public class TreeUtil {
    /**
     * 两层循环实现建树
     *
     * @param treeNodes 传入的树节点列表
     * @return
     */
    public static <T extends TreeNode> List<T> bulid(List<T> treeNodes, Object rootId) {

        List<T> trees = new ArrayList<T>();

        for (T treeNode : treeNodes) {
            if (rootId == null) {
                if (treeNode.getParentId() == null) {
                    trees.add(treeNode);
                }
            } else {
                if (rootId.equals(treeNode.getParentId())) {
                    trees.add(treeNode);
                }
            }

            for (T it : treeNodes) {
                if (it.getParentId() != null && it.getParentId().equals(treeNode.getId())) {
                    if (treeNode.getChildren() == null) {
                        treeNode.setChildren(new ArrayList<TreeNode>());
                    }
                    treeNode.add(it);
                }
            }
        }
        return trees;
    }

    /**
     * 使用递归方法建树
     *
     * @param treeNodes
     * @return
     */
    public static <T extends TreeNode> List<T> buildByRecursive(List<T> treeNodes, Object root) {
        List<T> trees = new ArrayList<T>();
        for (T treeNode : treeNodes) {
            if (root.equals(treeNode.getParentId())) {
                trees.add(findChildren(treeNode, treeNodes));
            }
        }
        return trees;
    }

    /**
     * 递归查找子节点
     *
     * @param treeNodes
     * @return
     */
    public static <T extends TreeNode> T findChildren(T treeNode, List<T> treeNodes) {
        for (T it : treeNodes) {
            if (treeNode.getId() == it.getParentId()) {
                if (treeNode.getChildren() == null) {
                    treeNode.setChildren(new ArrayList<>());
                }
                treeNode.add(findChildren(it, treeNodes));
            }
        }
        return treeNode;
    }

    public static <T extends TreeNode> T findChildrenEx(T treeNode, List<T> treeNodes) {
        for (T it : treeNodes) {
            System.err.println("it: "+it.getId()+"treenode: "+treeNode.getId());
            if(it.getId().equals(treeNode.getId())){
                return it;
            }else{
                List<TreeNode> subTrees=it.getChildren();
                if(subTrees!=null && subTrees.size()>0){
                    T subTreeNode =findChildrenEx(treeNode, (List<T>) subTrees);
                    if(subTreeNode!=null){
                        return subTreeNode;
                    }
                }

            }
        }
        return null;
    }

}
